Ventilator system for recirculation of air and regulating indoor air temperature

ABSTRACT

An air circulator for amplifying and manipulating high volumes of low velocity air in order to circulate and regulate indoor air temperature within a commercial or an industrial environment. The air circulator includes a housing and a support member. The housing has an airflow passageway with a bottom end defining an air intake and a top end defining an air outlet. The air circulator further includes a fan positioned within the airflow passageway of the housing substantially adjacent to the top end of the housing. The support member supports the housing so as to dispose the air intake above the ground. The fan and the air outlet are configured to discharge air having a significant vertical component and a significant lateral component.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/174,597 filed on May 1, 2009 and entitled “SYSTEM FOR REGULATING INDOOR AIR TEMPERATURE”, the entire contents of which are hereby incorporated by reference herein for all purposes.

TECHNICAL FIELD

The embodiments herein relate in general to apparatus and systems for air distribution and circulation, and in particular, to ductless apparatus and systems for circulating high volumes of low velocity air to regulate indoor air temperature.

INTRODUCTION

Heating, ventilation and air conditioning (HVAC) systems generally contribute to the comfort and satisfaction of workers, customers and tenants within indoor spaces by controlling and regulating air temperature. Properly tuned, HVAC systems can help improve employee productivity and contribute to good air quality. However, HVAC systems are often very inefficient and account for some of the highest energy costs in industrial and commercial environments.

It is now quite common for commercial buildings, especially newer buildings, to have large open spaces with high ceilings. Often such buildings are “open concept” facilities with minimal or no vertical walls. New challenges are presented in addressing air movement in such large open spaced facilities. In particular, conventional HVAC systems are generally poor at circulating air throughout these large open spaces. Due to this poor air circulation, discrete layers of warm and cool air tend to separate, with warm air rising towards the ceiling, while cooler air settles near the floor. Depending on operating conditions, the temperature differential between the floor and the ceiling can be quite high, in some case as much as 20 degrees Fahrenheit (or more).

Some known devices have been developed that attempt to improve air circulation. For example, U.S. Pat. No. 5,078,574 (Olsen) describes floor to ceiling room temperature gradients being minimized by a portable floor mounted upstanding tubular unit having air intake ports adjacent the bottom, an open top with air directing louvers, and an electric motor driven fan having blades spanning the interior of the tube above the ports and substantially below the open top. According to Olsen, the unit can be positioned on the floor of a room in an out of the way location and will circulate air throughout the room without causing a draft to minimize temperature variations between the floor and the ceiling of the room. The unit receives air adjacent the floor and projects it in a substantially confined upstanding column to the ceiling where it dissipates throughout the room area to flow back to the intake ports of the unit.

Another known approach, U.S. Pat. No. 4,347,782 (Hoecke) discloses a device which recirculates air to raise air temperature near the floor (in winter), and to provide a direct flow of air blown generally horizontally slightly above persons standing on the floor (in summer). A fan assembly is housed in a unitary duct-like housing, which is open near its base to take in air. The duct-like housing is capped with an outlet hood, which adjustably telescopes on the housing so that air flow from openings in the outlet hood can be adjusted for winter or summer operation.

Another approach is discussed in U.S. Pat. No. 4,103,146 (Rampe). Rampe discloses an apparatus for ductlessly circulating large volumes of air in industrial facilities and the like. The apparatus includes an upstanding structure, which defines a vertically extending chamber. Openings are provided in lower and upper portions of the structure and communicate the chamber with lower and upper strata of ambient air. A blower assembly is housed within the structure intermediate the lower and upper openings. According to Rampe, in operation the apparatus is positioned substantially centrally in a room and the blower assembly is energized to move air upwardly through the chamber. The lower and upper openings are arranged such that air from the lower strata is drawn substantially radially toward the lower openings, and such that air discharging from the upper openings into the upper strata moves substantially radially outwardly toward walls of the room. According to Rampe, the effect of this type of operation is to establish a primary substantially toroidal air flow circulation beside the apparatus, and to induce the establishment of a secondary substantially toroidal air flow circulation above the apparatus. These primary and secondary circulation torri promote a thorough intermixing of air from all parts of the room and promote temperature uniformity throughout the room.

In spite of these known devices, the inventor has identified a need for new or improved apparatus and systems for regulating indoor air temperature.

SUMMARY

According to one aspect there is provided a ductless air distribution system for amplifying and/or manipulating high volumes of low velocity air in order to circulate and regulate indoor air temperature.

In accordance with another aspect there is provided a portable or permanent ductless air distribution system for amplifying and/or manipulating high volumes of low velocity air in order to circulate and regulate indoor air temperature within a commercial or industrial environment using one or more natural air streams. The system includes a support member and a housing having a top end and a bottom end. The system further includes a fan assembly mounted above the bottom end and below the top end of the housing. An air intake may be positioned across the bottom end of the housing. An air outlet may be positioned across the top end of the housing and may incorporate a self-regulating control system. The support member supports the housing above the ground so that the air intake may be positioned directly in the natural air stream generated by the air distribution system.

Conveniently, the system may be used in both the winter and summer. In some cases the system may change the air within an industrial environment two to four times every hour. Furthermore, the system may be sized and configured to operate such that the temperature differential between the ceiling and the ground may be within one to two degrees Fahrenheit during use.

Some embodiments as described herein relate to systems and methods for controlling environmental parameters within an indoor environment using methods of forced mechanical convection to induce, amplify and/or manipulate the effects of natural convection phenomena, including at least one of the air de-lamination phenomena and the Coanda effect, to provide generally complete air distribution, circulation, de-stratification, and mixing of air within an indoor environment.

In some embodiments, some advantages provided by the systems and apparatus as described herein may include equalization of the temperature throughout an industrial or commercial environment (e.g. between the ceiling and ground level), elimination of hot and cold spots (e.g. for improving comfort), elimination of drafts from ceiling fans, improved air quality, reduction in energy consumption, and self-regulation.

According to another aspect, there is an apparatus for circulating air. The apparatus includes a housing having an airflow passageway with a bottom end defining an air intake and a top end defining an air outlet, and a support member for supporting the housing and for disposing the air intake above a support surface. The apparatus also includes a fan positioned within the airflow passageway of the housing substantially adjacent to the top end of the housing, and a drive coupled to the fan for operating the fan so as to blow air from the air intake to the air outlet.

The fan and the air outlet may be configured such that the air exiting the air outlet has a flow direction with a significant vertical component and a significant lateral component. In some embodiments, the vertical component may be between about 40% to 80% of the total airflow, and the lateral component may be between about 60% to 20% of the total flow. In some embodiments, the vertical component may be about 60% of the total airflow, and the lateral component may be about 40% of the total airflow.

A first height may be defined between the fan and the top end of the housing, and a second height may be defined between the bottom end of the housing and the top end of the housing. In some embodiments, the first height may be less than half of the second height. Furthermore, in some embodiments, the first height may be less than one third of the second height. Further still, in some embodiments, the first height may be about one tenth of the second height.

The fan may be positioned between about 0 inches and about 10 inches below the top end of the housing.

The apparatus may include at least one air filter for filtering air passing through the airflow passageway of the housing. The air filter may be positioned at least 20 inches below the fan.

A second height may be defined between the bottom end of the housing and the top end of the housing, and a third height may be defined between the at least one filter and the fan. In some embodiments, the third height may be more than about half of the second height. Furthermore, in some embodiments, the third height may be more than about two thirds of the second height.

The at least one air filter may have a rectangular shape.

The at least one air filter may define a filtration surface area. Furthermore, the airflow passageway of the housing may have a cross-sectional area less than the filtration surface area.

According to another aspect, there is an apparatus for circulating air. The apparatus includes a housing having an airflow passageway with a bottom end defining an air intake and a top end defining an air outlet, and a support member for supporting the housing and for disposing the air intake above a support surface. The apparatus also includes a fan positioned within the airflow passageway of the housing, and a drive coupled to the fan for operating the fan so as to blow air from the air intake to the air outlet. The fan and the air outlet are configured such that the air exiting the air outlet has a flow direction with a significant vertical component and a significant lateral component.

The fan may be positioned substantially adjacent to the top end of the housing.

According to another aspect, there is a system for circulating air. The system comprises an air circulator including a housing having airflow passageway with a bottom end defining an air intake and a top end defining an air outlet, and a support member for supporting the housing and for disposing the air intake above a support surface. The air circulator also includes a fan positioned within the airflow passageway of the housing, and a drive coupled to the fan for operating the fan so as to blow air from the air intake to the air outlet. The system also comprises a first temperature sensor for measuring air temperature in a lower portion of a building, and a second temperature sensor for measuring air temperature in an upper portion of the building. Furthermore, the system comprises a controller for determining a temperature differential based on measurements from the first and second temperature sensors. The controller operates the fan based on the temperature differential.

The controller may adjust a fan speed for the fan based on the temperature differential. Furthermore, the controller may output an AC electrical signal having a frequency for operating the fan, and wherein the controller adjusts the frequency to control the fan speed. The AC electrical signal output by the controller may have a substantially constant voltage.

The fan may be positioned substantially adjacent to the top end of the housing.

Other aspects and features will become apparent, to those ordinarily skilled in the art, upon review of the following description of some exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are for illustrating various examples of articles, apparatus, systems and methods of the present specification and are not intended to limit the scope of what is taught in any way. In the drawings:

FIG. 1 is a perspective view of an air circulator according to one embodiment;

FIG. 2 is a cross-sectional view of the air circulator of FIG. 1 taken along line 2-2;

FIG. 3 is a schematic diagram of an airflow pattern generated by the air circulator of FIG. 1 within an indoor environment;

FIG. 4 is a schematic diagram of an airflow pattern generated by a prior art air circulator within the same indoor environment as in FIG. 3;

FIG. 5 is a schematic diagram of a system for circulating air within a building according to another embodiment;

FIG. 6 is a perspective view of an air circulator according to yet another embodiment; and

FIG. 7 is a cross sectional view of the air circulator of FIG. 6 taken along line 7-7.

DETAILED DESCRIPTION

A number of factors and phenomena have been recognized herein as being worthy of consideration when designing apparatus and systems for circulating air.

One factor is de-lamination. De-lamination is a phenomenon whereby warm airflows and cool airflows tend to repel one another. For example, an upper layer of warm air will tend to float on top of a lower layer of cool air, generally without mixing between the layers. The upper and lower layers may be referred to as “stratified layers” having stratified layer “heights”. De-lamination is a result of different air temperatures, densities and turbulence intensity between cool and warm airflows, and generally results in energy waste and/or reduced efficiencies within an HVAC system.

It has been discovered that with higher velocity airflow, the temperature dependant de-lamination phenomenon begins to disappear, such that the heights of stratified layers tend to decrease.

For instance, in one example with stratified layers, if the airflow velocity is 1.2 m/s and the temperature differential between the hot and cold layers is 30° F., the stratified layer height (e.g. the height of each layer) might be about 1.4 meters. However, if the airflow velocity is increased to about 1.6 m/s in the same environment, the stratified layer height may reduce to about 0.7 meters. Furthermore, as the airflow velocity increases beyond about 2.0 m/s, the stratified layer height will tend to decrease further, and may in fact approach zero.

Similarly, as the temperature differential between the hot and cold layers decreases, the stratified layer height also tends to decrease. For example, if an airflow velocity of 1.2 m/s and a temperature differential of about 30° F. might correspond to a stratified layer height of about 1.4 meters, while if the temperature differential between the hot and cold layers was 10° F., the stratified layer height might approach zero.

When the stratified layer height is larger, this tends to promote repelling of hot and cold layers (e.g. mixing of the layers of hot and cold air is inhibited). Conversely, when the stratified layer height is smaller, this tends to promote mixing between the hot and cold layers. Accordingly, it has been discovered that controlling airflow velocity can influence whether hot and cold layers of air tend to repel each other, or whether the layers of air tend to mix with each other.

Another phenomenon that affects airflow is the Coanda effect. The Coanda effect is the tendency of a moving fluid jet to stay attached to an adjacent or nearby surface.

For example, air-conditioning systems may exploit the Coanda effect to increase the distance traveled by cool air using a ceiling-mounted diffuser. In particular, a ceiling-mounted diffuser may take advantage of the Coanda effect by discharging air near the ceiling. The discharged air will tend to “stick” to the ceiling while traveling away from the diffuser. Accordingly, the cool air may travel further along the ceiling before tending to drop down towards the ground (in comparison to mounting the diffuser in free air without the neighboring ceiling, where the cooled air will tend to fall more quickly).

In some embodiments, apparatus and systems for circulating air as described herein may attempt to use at least one of the de-lamination phenomenon and the Coanda effect.

Referring now to FIGS. 1 and 2, illustrated therein is a ductless air distribution apparatus or “air circulator” 20 made in accordance with one embodiment. The air circulator 20 generally includes a housing 22 and a support member 30 for supporting the housing 22 above a ground surface (e.g. the floor of a building).

The housing 22 generally has a bottom end 24, a top end 26, and an airflow passageway 28 located therebetween (as shown in FIG. 2). The bottom end 24 defines an air intake, while the top end 26 defines an air outlet.

The air circulator 20 also includes a fan 32 and a drive 34. The fan 32 is mounted in the airflow passageway 28 of the housing 22 between the bottom end 24 and the top end 26, and generally adjacent the top end 26. The drive 34 is coupled to the fan 32 for rotating the fan 32 so as to blow air through the airflow passageway 28 from the air intake (at the bottom end 24) to the air outlet (at the top end 26).

In some embodiments, the drive 34 may be an electric motor having an output shaft 36 coupled to a central hub of the fan 32. In other embodiments, the drive 34 may have different configurations, for example, the drive 34 may be coupled to the fan 32 using pulleys (for example as shown in FIG. 7).

Generally, the fan 32 and drive 34 enable the air circulator 20 to amplify and manipulate high volumes of low velocity air in order to circulate and regulate indoor air temperature, for example within a commercial or industrial environment. In particular, the fan 32 and the air outlet are generally configured to discharge an airflow from the air outlet having both a significant vertical component and a significant lateral component. In other words, the air circulator 20 blows air both vertically upwards and laterally outwards relative to the top end 26 of the housing 22. This configuration tends to promote air circulation and mixing of the warm and cool layers of air, as will be described below.

In some embodiments, the housing 22 may include a plurality of side panels 38 (e.g. four panels as shown in the illustrated embodiment), which may be metal, plastic or another suitable material. In some embodiments, the panels 38 may be sized and shaped so that the housing 22 has a box-like shape. In particular, the housing 22 may be shaped as a vertically oriented square tube, with the airflow passageway 28 extending generally vertically through the center of the tube.

The support member 30 generally supports the housing 22 above the support surface (e.g. a floor within a commercial or industrial building) so that the air intake is positioned at least partially within in the natural air stream generated by the air circulator 20 (as shown in FIG. 3).

The support member 30 may include a plurality of leg members 40 sized and shaped to allow air to flow into the air intake. In the illustrated embodiment, there are four leg members 40 interconnected by cross-members 42. Generally, the leg members 40 and cross-members 42 are sized and shaped so as to not inhibit airflow into the air intake.

In some embodiments, one or more of the leg members 40 may be supported by caster wheels 44, which may allow the air circulator 20 to be moved by rolling the air circulator 20 along the ground surface (e.g. to different locations within an industrial building).

In other embodiments, the support member 30 may be fixed to the ground surface. For example, the support member 30 may include leg members 40 that are bolted to the ground surface.

In the illustrated embodiment, the air intake encompasses the entire bottom end 24 of the housing 22, and the air outlet encompasses the entire top end 26 of the housing 22. However, in other embodiments the air intake and air outlet may encompass less than the entire bottom end 24 and top end 26, respectively, of the housing 22.

In some embodiments, the housing 22 may include a lower protective grill 50 and an upper protective grill 52. The grills 50, 52 generally have one or more openings that are sized and shaped to allow airflow to pass therethrough, but which prevent undesired objects, such as hands or fingers, from entering the airflow passageway 28. The grills 50, 52 may be designed to minimally impede the airflow through the air intake and the air outlet. In some examples, one or both of the grills 50, 52 may be removably coupled to the housing 22.

In some embodiments, the removable upper grill 52 is located as close as possible to the fan 32.

As mentioned above, the fan 32 and the air outlet are generally configured such that air exiting the air outlet has a flow direction with both a significant vertical component and a significant lateral component. In some embodiments, this may be achieved by positioning the fan 32 substantially adjacent to the air outlet (i.e. adjacent the top end 26 of the housing 22).

For example, the fan 32 may be separated from the top end 26 by a distance corresponding to a first height H1 as shown in FIG. 2. In some embodiments, the first height H1 may be between about 0 inches and about 10 inches. In some embodiments the first height H1 might be between 2 inches and 8 inches. In some embodiments, the first height H1 may be about 4 inches.

In some embodiments, the distance between the bottom end 24 and the top end 26 may define a second height H2. Furthermore, the first height H1 may be defined relative to the second height H2. For example, the first height H1 may be less than half of the second height H2. In some embodiments, the first height H1 may be less than one third of the second height H2. In some embodiments, the first height H1 may be about one tenth of the second height H2.

In some embodiments, the top end 26 of the housing 22 may include a guide 54, such as a shroud or a panel with a cylindrical cut-out. The guide 54 may at least partially encase the fan 32 and direct airflow from the fan 32 out of top end 26 through the air outlet (and may assist in imparting one or both of the significant vertical component and significant lateral component to the airflow).

For example, the guide 54 may deflect air traveling upwards through the airflow passageway 28 to inhibit the discharged air from traveling substantially laterally at a certain height above the ground surface (e.g. at a height corresponding to the occupant head height), and to project a substantial column of air vertically towards the ceiling. This configuration may provide comfort to occupants standing near the air circulator 20 (e.g. by deflecting air leaving the air circulator 20 so that it does not directly strike the occupants). This configuration may also promote air circulation using the de-lamination phenomenon and the Coanda effect.

In some embodiments, the guide 54 may be generally circular and may be sized slightly larger than the diameter of the fan 32. In some embodiments, the guide 54 may be up to about 2 inches larger than the diameter of the fan.

Referring now specifically to FIGS. 3 and 4, the air circulator 20 described herein tends to promote better air circulation over a wider area in comparison to prior art air circulators.

FIG. 3 illustrates a simulated airflow induced by the air circulator 20 described herein, which discharges an airflow having both a significant vertical component and a significant horizontal component. By comparison, FIG. 4 illustrates a simulated airflow induced by a prior art air circulator having a significant vertical component but no significant horizontal component.

In some embodiments, the air circulator 20 may provide a vertical component that is between about 40% to 80% of the total airflow, and a lateral component that is between about 60% to 20% of the total airflow. In some embodiments, the vertical component may be about 60% of the total airflow and the lateral component may be about 40% of the total airflow.

Providing an airflow having both a significant vertical component and a significant horizontal component may tend to promote air circulation over a wider area, which tends to promote de-stratification of the surrounding air and a reduction in temperature differentials within an indoor environment.

By configuring the air circulator 20 to discharge an airflow having both a significant vertical component and a significant horizontal component, the air circulator 20 can take advantage of at least one of the de-lamination phenomenon and the Coanda effect.

Regarding de-lamination, the lateral component of the discharged airflow tends to have a lower temperature in comparison to adjacent air because the air circulator 20 takes cooler air near the floor and blows it into warmer air that is located higher up above the floor. Provided that the discharge airflow has a sufficiently low velocity to avoid de-stratification for a given temperature differential between the cool air and warm air, the cool air and the warm air tend to repel each other such that one floats on the other with limited heat and mass transfer therebetween. Since the cool and warm air repel each other, the cool airflow tends to travel further laterally outward before mixing with the warm air (thus extending the effective mixing range of the air circulator 20).

Using the repelling nature of warm and cool air to encourage mixing is counterintuitive because many prior art HVAC systems want to promote mixing as quickly as possible so as to de-stratify air within an indoor environment. However, promoting mixing (e.g. through turbulent flow) tends to reduce the distance that the discharged cool air can travel because it mixes with nearby stationary warm air and loses its lateral momentum. This tends to result in a de-stratified area localized around the air circulator, but other areas further from the air circulator remain stratified and tend to have significant temperature differentials between the ceiling and the floor.

In contrast, the present air circulator 20 takes advantage of the repelling effect between warm and cool airflows and enables discharged air to travel further laterally outwards from the air circulator 20 and cover a substantially broader lateral area.

Regarding the Coanda effect, the vertical component of the airflow is generally configured to impinge the ceiling such that the airflow spreads out laterally along the ceiling. Due to the Coanda effect, this component of the discharged airflow tends to stay attached to, or at least adjacent to, the ceiling and thus tends to spread out laterally further from the vertical component of the airflow before falling down and mixing with the warmer air below.

The outward spreading along the ceiling is further enhanced by the de-lamination phenomenon, since the discharged airflow that moves along the ceiling is cooler than the warmer air it replaced. Accordingly, the cooler discharged air tends to repel the warmer air in the same way as described previously so as to increase the lateral distance traveled along the ceiling by the cooler air.

The combined effect of the significant vertical component and the significant horizontal component means the discharged airflow tends to spread out over greater lateral distances in comparison to prior art systems. Accordingly, the air circulator 20 tends to promote de-stratification over a wider interior space in comparison to known prior art air circulators.

Another benefit of the present air circulator 20 is that the air discharged generally does not require ducting. Ducting tends to be costly to ship and install and also introduces frictional losses due to interactions between the airflow and the interior surfaces of the ducting (and which tend to increase the power requirements for circulating air).

The air circulator 20 also utilizes the Coanda effect at the air intake of the housing 22. For example, air discharged from the air circulator 20 eventually pushes warmer air downward toward a lower portion of the indoor environment (e.g. towards the floor). The air circulator 20 then draws this air in through the air inlet at the bottom end 24, which tends to induce an air current that travels across the floor. This air current along the floor tends to stay attached to the floor (according to the Coanda effect).

Generally, the air circulator 20 works to gently pull cool air across the floor. In some embodiments, the air circulator 20 may pull air from over two hundred feet away. Discharged air is propelled upward and outward across the upper level (e.g. ceiling). At the same time, drawing cool air from the floor into the air circulator 20 creates a low-pressure layer, which pulls the warmer air near the ceiling back down to the ground.

Accordingly, the air circulator 20 tends to create a natural rolling airflow pattern, which mixes the cool air with the warm air and reduces the temperature gradient within the building.

Furthermore, placing the air circulator 20 within this natural rolling air stream and exposing the air stream to at least a portion of the air intake at the bottom end 24 of the air circulator 20 tends to increase the efficiency of the air circulator 20, which enables the air circulator 20 to de-stratify the air and reduce temperature gradients faster. As a result, the air circulator 20 tends to quickly de-stratify the air and equalize the temperature differential within a few degrees Fahrenheit.

Generally, the air circulator 20 can equalize temperatures within a building during both the summer and winter. By way of example, during the winter the warm air from the building heating system tends to collect at the top of a building (e.g. in an atrium). The air circulator 20 can bring this warm air down to floor level or occupant level.

During the summer, the cool air or conditioned air may have difficulty reaching the top portion of an atrium because it tends to settle at the bottom of the building near the floor. The air circulator 20 can distribute the cool air that is collected near the floor back up to the top. Accordingly, the air circulator 20 may be used to maintain overall improved comfort levels in operation during both summer and winter seasons.

In some embodiments, the air circulator 20 can increase the overall efficiency of existing HVAC systems by 20% or more. The air circulator 20 may also reduce the short cycling on/off of the existing HVAC rooftop units and unit heaters (e.g. by stabilizing the on and off cycles). Accordingly, the air circulator 20 may reduce electrical power consumption and may allow a building to downsize HVAC rooftop blower motors, which may result in energy savings. In some embodiments, the air circulator 20 may be used to replace ceiling fans.

The present air circulator 20 may also have the ability to capture and distribute latent heat produced by manufacturing equipment, which can further enhance efficiencies. For example, the natural rolling airflow that passes along the floor tends to pick up heat generated by manufacturing equipment. This heat capture ability can reduce operator fatigue by sweeping the heat from their work areas and generally equalizing temperatures throughout an indoor work environment.

The air circulator 20 may also reduce heat losses through the ceiling and walls of a building. For example, heat losses occur when warm air within the building transfers heat to the cooler air outside the building through the walls and ceiling. These heat losses tend to increase as the temperature differential between the inside air and the outside air increases.

When there is no air circulation, warmer air tends to rise and collect in a stratified layer near the ceiling. This layer of warm air tends to increase both the temperature differential and the heat losses through the ceiling. In contrast, the air circulator described herein circulates air within the building and inhibits the formation of a stratified layer of warm air by mixing it with cooler air closer to the floor. Accordingly, the air circulator may reduce the air temperature near the ceiling, which may reduce both the temperature differential and heat losses.

In some embodiments, the height of the air intake above the ground can be important because it sets the height at which incoming air is drawn into the fluid passageway 28. For example, when the height of the air intake is lowered, incoming air is drawn from a lower height, which generally corresponds to cooler air. Drawing in cooler air tends to provide more efficient air circulation and de-stratification because it tends to utilize the maximum (or at least a significant) temperature differential between the air near the ground and the air near the ceiling. However, the air intake should be set above the ground some minimum height, otherwise static pressure increases and tends to reduces the efficiency of the air circulator 20.

As shown in FIG. 2, the height of the air intake above the ground corresponds to a clearance height C. For example, in some embodiments the clearance height C of the air intake may be between one foot and four feet above the ground. In some embodiments, the clearance height C of the air intake above the ground may be about two feet.

Setting the air intake height to about two feet may be useful when using the air circulator 20 near a loading dock door area. For example, air above the two-foot level tends to remain at the existing temperature set point for the HVAC system (e.g. 70 degrees Fahrenheit or some other set point).

Furthermore, the air circulator 20 tends to force the air from outside the loading dock door to remain below the two-foot level. Accordingly, in the winter, loading dockworkers will tend not to feel the cold air from outside the loading dock because it is kept at a low height. Once the dock door is closed, the air circulator 20 can reduce the heat recovery time for that area. For example, in some cases, the temperature of the area may be brought back up to the desired temperature within minutes by circulating air in the loading dock area with air throughout the rest of the building.

In some embodiments, the air circulator 20 may include an outlet adjustment mechanism for adjusting the size of the air outlet. For example, the outlet adjustment mechanism may increase or decrease the radius of the circular guide 54. Adjusting the size of the air outlet enables the air circulator 20 to alter the vertical and/or lateral components of the airflow, for example, to manipulate the de-lamination phenomenon and/or the Coanda effect depending on the particular configuration of the building, or the air temperatures within the building.

The outlet adjustment mechanism may adjust the size of the air outlet between a first size and a second size, with the second size being smaller than the first size. Generally, the larger first size allows the fan to blow more air laterally outward relative to the housing 22 in comparison to the second size. Accordingly, the larger first size may utilize the de-lamination phenomenon to a greater extent. The smaller second size may allow the fan to blow more air upward relative to the housing in comparison to the first size. Accordingly, the smaller second size may utilize the Coanda effect to a greater extent.

Adjusting the size of the air outlet may be beneficial when dealing with varying ceiling heights. If the ceiling height is low in relation to the discharge of the air circulator 20, the radius of the guide 54 could be increased to allow for more lateral airflow.

Furthermore, the adjustment mechanism may include louvers (not shown) for directing air discharged from the air outlet. For example, if an obstacle was preventing the air circulator 20 from functioning as desired, the louvers could be positioned to direct airflow around the obstacle. An example of this would be when the air circulator 20 is located within proximity to an interior partition or wall and the louvers could direct airflow around the wall.

In some embodiments, the louvers could also be used to adjust the vertical and lateral components of the airflow.

An alternative to increasing and decreasing the radius of the circle would be to provide a plurality of different removable upper grills 52, each of which may act as different type of diffuser. For example, each upper grill 52 could provide a different diffusion pattern for the discharged air, which may be used to alter or manipulate the de-lamination phenomenon and/or Coanda effect.

By changing diffusers or making the air outlet adjustable, for example, either automatically or manually, it may be possible to adjust or change the discharge airflow for summer and winter operation. For example, the air circulator 20 may include a different diffusion pattern for summer and winter applications (e.g. the summer diffuser could take advantage of the Coanda Effect in an effort to distribute the cooler air-conditioned air over a larger area by keeping the cooler air attached or adjacent to the ceiling plane).

If the ceiling height of the space being serviced by the air circulator 20 is too high to justify utilization of the Coanda Effect (e.g. the airflow may diffuse before impinging the ceiling), a different summer diffuser design could be designed with a different diffusion pattern to take advantage of the de-lamination phenomenon (e.g. the float and repelling effects) by discharging the air in a more substantially lateral direction. In this example, the air circulator 20 might also reduce the actual volume of air being serviced by effectively decreasing the size of the building such that warm air near the ceiling remains un-serviced during the summer months. This may be desirable because servicing the warmer air near the ceiling might actually increase the load on the air conditioning unit.

In some embodiments, the air circulator 20 uses a 36-inch diameter fan 32. However, generally any size fan 32 will work depending on the size of the area being serviced. For example, in a large area a large fan (or multiple fans) can be used, while in a small area the fan size can be reduced. Generally, the housing 22 for the fan 32 may be a few inches larger than the diameter of the fan 32.

By way of example, in some embodiments the air circulator 20 may be effective in a space that is about 10,000 square feet or more. In particular, an air circulator 20 with a 36-inch fan 32 may work effectively within a 10,000 square foot building having a twenty foot high ceiling such that air changes occur two to four times per hour.

While the air circulator 20 may work well in a 10,000 square foot building, the air circulator 20 may be effective in a variety of different building sizes (e.g. larger than 10,000 square feet, smaller than 10,000 square feet, and so on). In some embodiments, multiple air circulators 20 can be used in larger spaces.

In some embodiments, a plurality of smaller air circulators can be used to replace one large air circulator, or visa versa. The number and size of air circulators utilized may depend upon desired aesthetics, fan noise levels, floor space, and the size of fan that can be used within a pre-determined amount of space.

It may be possible to estimate the relationship of the size of building to the size of the required air circulator using a sizing calculation. The sizing calculation is based on the total volume of air within a space divided by the flow rate (e.g. cubic feet per hour) that the air circulator can move. The calculation determines the time it takes the air circulator to theoretically service all of the air within the space. A similar sizing calculation utilizes the flow rate divided by the volume of air within the space so as to determine the theoretical number of air changes per hour within the building.

The amount of air circulation may change between summer and winter operation. By way of example, it might be desirable in the summer to increase the amount of air changes per hour in an effort to increase the velocity of the air at occupant height so as to create a greater cooling effect. In the winter, it might be desirable to lower the number of air changes per hour and corresponding air velocity in an effort to reduce the chilling effect and increase occupant comfort. Accordingly, the sizing calculation may take into account the air changes per hour desired for both summer and winter operation.

In some embodiments, the air circulator 20 may include a self-regulator or controller 70 for controlling the air circulator 20. For example, referring to FIG. 2, the controller 70 may be operatively coupled to the drive 34 for controlling the speed of the fan 32. In particular, the controller 70 may provide electrical power to the drive 34 through a cable 72 and may adjust the amount of power supplied to control the speed of the fan 32. Furthermore, the controller 70 may receive electrical power from a source such as a 120V wall socket through a plug 74 on the outside of the housing 22 as shown in FIG. 1. In other embodiments, the controller 70 may control other aspects of the air circulator 20, such as the air outlet adjustment mechanism.

As shown in the illustrated embodiment, the controller 70 may include a touch screen 76 for adjusting parameters. For example, the touch screen 76 may enable a user to select the desired temperature for the indoor environment.

The touch screen 76 may allow the user to select other parameters such as the fan speed or the horizontal or vertical components of the discharge airflow. The user may select these setting using one of several presets. In generally, these parameters can help the user regulate the temperature throughout the indoor environment.

Referring now to FIG. 5, illustrated therein is an air circulation system 100 made in accordance with another embodiment. The system 100 is generally used to circulate air within an indoor environment such as a building 102, which may be a commercial building or an industrial building.

The system 100 includes an air circulator 120, which may be similar to the air circulator 20 described previously, and similar elements are given similar reference numerals incremented by one hundred. For example, the air circulator 120 includes a housing 122, a support 130, a fan 132 and a drive 134.

The system 100 also includes two temperatures sensors 160, 162 and a controller 170 in communication with the temperature sensors 160, 162. The first temperature sensor 160 is for measuring a first air temperature T1 in a lower portion of the building 102, and the second temperature sensor 162 is for measuring a second air temperature T2 in an upper portion of the building 102.

The controller 170 controls the air circulator 120 based on the first and second temperatures T1 and T2. The controller 170 may be similar to the controller 70 described previously. For example, in some embodiments, the controller 170 may be part of the air circulator 120. In other embodiments, the controller 170 may be located separately from the air circulator 120. For example, the controller 170 may control multiple air circulators and the controller 170 may be in remote communication with each of the air circulators.

Operation of the system 100 commences by detecting a first air temperature T1 from the first temperature sensor 160 near the ground level of the building 102 and detecting a second air temperature T2 from the second temperature sensor 162 near the ceiling of the building 102. The controller 164 then calculates a temperature differential based on the first and second temperatures T1 and T2, and then operates the air circulator 120 based on the calculated temperature differential. For example, if the temperature differential is above a threshold value, which indicates the air within the building is stratified, the controller 170 might turn on the air circulator 120 by sending a signal to the drive 134. The controller 170 may continue monitoring the temperature differential so that once the temperature differential is below a threshold value, the controller turns off the air circulator 120.

The controller 170 may operate other aspects of the air circulator 120 based on the temperature differential. For example, the controller 170 may adjust the speed of the fan 132 based on the temperature differential. For example, if the temperature differential is high, the controller 164 may operate the drive 134 at a higher speed. If the temperature differential is low, the controller 164 may operate the drive 134 at a lower speed. In some embodiments, the controller 64 may operate the drive 134 at one of several preset speeds. In other embodiments, the controller 164 may operate the drive 134 using an analogue type signal that allows a continuous range of speeds, as will be described below.

The controller 164 may also adjust the operating speed of the drive 134 based on other events. For example, if there is a change in the indoor environment such as a door opening, the controller 164 may increase the speed of the drive 134, for example, up to full speed. When the door closes, the controller 164 may decrease the speed back down to the previous speed.

The controller 170 may also control the outlet adjustment mechanism or other aspects of the air circulator 120 so as to adjust the vertical and lateral components of the airflow discharged from the air circulator 120.

In some embodiments, the system 100 may control the speed of the fan 132 by adjusting the frequency of a signal sent to the drive 134. For example, the controller 170 may receive a 120VAC two-phase signal and convert it to a three-phase AC signal that is output to the drive 134. The controller 164 may use the three-phase AC signal to control the speed of the drive 134 by adjusting the frequency of the three-phase AC signal. This method of control may have advantages over the prior art.

Prior art systems tend to control the speed of the drive by adjusting the voltage using a rheostat, which has numerous drawbacks. For example, the rheostat in these systems often produces a noticeable motor hum, in part, due to the size of the drive (e.g. motor) required to produce the optimal amount of air-changes-per-hour. In contrast, utilizing the system 100 described above to adjust fan speed based on frequency tends to reduce motor hum and noise and allows the user to tune the system 100 (e.g. by adjusting fan speed) for a specific application or building environment.

In some embodiments, the self-regulating control system 100 may continue operating even after an industrial or a commercial facility is de-stratified, for example, such that the fan 132 operates at a reduced speed. Operating the fan 132 at reduced speed can help maintain de-stratification within the building, for example, to within a temperature differential of about 1° F. to 2° F. for some buildings. Once the air current is induced in a building, it is easy to maintain using discharged air with less velocity.

The system 100 may adjust the fan speed for other purposes. For example, the system 100 can to be tuned to meet the desired effects for occupants. An example would be to vary the fan speed between summer and winter to produce a wind chill effect induced by higher speed air currents. By speeding the current up in the summer it allows for an occupant to perceive the temperature as being cooler than it actually is, for example, by as much as three or more degrees Fahrenheit. In the winter, the current speed can be reduced to reduce the wind chill effect so as to increase the perceived temperature felt by occupants. The system 100 may also turn the air circulator 120 off during the night when the space is un-occupied.

Another reason for adjusting the fan speed is to create “vertical air curtains” at loading bay doors. For example, during the winter, it may be desirable to increase the speed of the fan, which may keep colder air outside the building below the air intake of the air circulator 120, and may prevent loading dock workers from feeling the cold air. Accordingly, when the loading bay door is opened, the system 100 automatically increases the fan speed. When the loading bay door is closed, the system 100 automatically slows the fan 132 down.

Similarly, during summer operation, it may be desirable to increase the velocity of the air current within the building when a loading bay door is opened, which may establish an “air curtain” and may also provide a wind chill effect.

Referring now to FIGS. 6 and 7, illustrated therein is an air circulator 220 made in accordance with an embodiment of the present invention. The air circulator 220 is similar in many respects to the air circulator 20 described previously and similar elements are given similar reference numerals incremented by two hundred.

The air circulator 220 includes a housing 222, a support 230, a fan 232, and a drive 234. The housing 222 has a bottom end 224 defining an air intake and a top end 226 defining an air outlet.

One difference is that the fan 232 is positioned further away from the top end 226 in comparison to the air circulator 20 described previously. In particularly, the height H1 between the top end 226 and the fan 232 is approximately 8 inches.

The housing 222 also includes a guide 254 encasing the fan 232. One difference is that the guide 254 has a slopped profile that narrows as it gets closer to the air outlet. This may help direct the airflow out of the air circulator 220, for example, so that the discharged air has a significant vertical component and a significant lateral component.

Another difference is that the drive 234 is coupled to fan 232 through a series of pulleys and a belt. In particular, one pulley 280 is coupled to the drive 234, which is in turn coupled to a second pulley 282 through a belt 284. The second pulley 282 is also coupled to a shaft 236, which is coupled to the hub of the fan 232.

The air circulator 220 also includes a controller 270, however, the controller 270 is located behind a plate 271 that is removably attached to the housing 222 for concealing the control panel 270. The controller 270 receives power from a power source through a power cord 274, which extends outward from the rear of the housing 222.

The air circulator 220 also includes one or more filters 280 that remove particulates from the air. The filters 280 may be MERV 8 filters, HEPA filters or another suitable air filter. As shown in the illustrated embodiment, the filters 280 are positioned on the support 230 between leg members 240 and cross-members 242 along the vertical sides of the support 230 and along the bottom side of the support 230 (shown in FIG. 7).

The filters 280 may be rectangular filters. Furthermore, the filters 280 may be of a standard rectangular size used in filtration industry.

The filters 280 may have a cumulative filtration surface area that is larger then the cross-sectional area of the airflow passageway 228. For example, in the illustrated embodiment, the filters 280 on the vertical sides of the support 230 increase the surface area tend to increase the filtration surface area in comparison to using one filter along the air intake 224 at the bottom of the housing 222. In particular, the filtration surface area is approximately three times larger than the cross-section of the airflow passageway 28. Increasing the filtration surface area tends to reduce the velocity of the air flowing through the filters 280, which may improve the effectiveness of the filters 280.

In some embodiments, the filters 280 may be located in different positions. For example, one filter may be positioned at the bottom end of the housing 222.

As shown, the fan 232 is generally spaced apart from the filters 280. Positioning the fan 232 closer to the top end 226 of the housing 222 tends to improve filtration. In particular, when the fan 232 is positioned closer to the bottom end 224, the speed of the air coming through the filters 280 tends to increase, which reduces the effectiveness of the filters 280. By placing the fan 232 further away from the bottom end 224, the speed of the air coming through the filters 280 decreases, which may improve the effectiveness of the filters 280.

Assuming the width of the cross-members 242 is minimal, the distance between the fan 232 and the filters 280 generally corresponds to a third height H3 between the fan 232 and the bottom end 224 of the housing 222. Generally, the third height H3 is at least about 20-inches. In the illustrated embodiment, the third height H3 is about 24-inches.

In other embodiments, the height of the fan 232 above the filters 280 may be defined in relative terms. In particular, the third height H3 may be defined relative to the second height H2 between the bottom end 224 and the top end 226 of the housing 222. For example, the third height H3 may be more than about half of the second height H2, or the third height H3 may be more than about two thirds of the second height H2. In the illustrated embodiment, third height H3 is about nine tenths of the second height H2.

By way of example, the inventor has determined that the air circulator 220 as described above and having a 36 inch fan 232, and using a 0.5 horsepower drive 234 provides an air speed between about 200 to 500 feet-pet-minute at about 10,000 cubic-feet-per-minute. The filtration provided by the air circulator 220 is comparable to other prior art systems, but the air circulator 220 uses about one third of the energy compared to the other prior art systems.

The air filters 280 can help reduce odours. For example, the air filters may incorporate charcoal cartridges that reduce or eliminate odours and chemical particulates from cleaning/sanitizing agents, or from other manufacturing processes. The air filters 280 may also reduce airborne allergens.

In some embodiments, the air circulator 220 may be adapted to provide fresh-air or “make-up air” capabilities, for example, by providing a length of ducting between the air intake and a source of fresh air (e.g. outside air).

The air circulator 220 may also be fitted with a heating source so as to heat air being circulated within an indoor environment. For example, the heating source may include a solar heating coil or a hydronic heating coil, or a heat source fueled by natural gas, oil, or electricity. The air circulator 220 may also be fitted with a cooling device such as an air conditioner.

While the above description provides examples of one or more apparatus, methods, or systems, it will be appreciated that other apparatus, methods, or systems may be within the scope of the present description as interpreted by one of skill in the art.

Other variations and modifications of the invention are possible. All such modifications or variations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto. 

1. An apparatus for circulating air comprising: a) a housing having an airflow passageway with a bottom end defining an air intake and a top end defining an air outlet; b) a support member for supporting the housing and for disposing the air intake above a support surface; c) a fan positioned within the airflow passageway of the housing substantially adjacent to the top end of the housing; and d) a drive coupled to the fan for operating the fan so as to blow air from the air intake to the air outlet;
 2. The apparatus of claim 1, wherein the fan and the air outlet are configured such that the air exiting the air outlet has a flow direction with a significant vertical component and a significant lateral component.
 3. The apparatus of claim 2, wherein the vertical component is between about 40% to 80% of the total airflow, and the lateral component is between about 60% to 20% of the total flow.
 4. The apparatus of claim 2, wherein the vertical component is about 60% of the total airflow, and the lateral component is about 40% of the total airflow.
 5. The apparatus of claim 1, wherein: a first height is defined between the fan and the top end of the housing; a second height is defined between the bottom end of the housing and the top end of the housing; and the first height is less than half of the second height.
 6. The apparatus of claim 1, wherein: a first height is defined between the fan and the top end of the housing; a second height is defined between the bottom end of the housing and the top end of the housing; and the first height is less than one third of the second height.
 7. The apparatus of claim 1, wherein: a first height is defined between the fan and the top end of the housing; a second height is defined between the bottom end of the housing and the top end of the housing; and the first height is about one tenth of the second height.
 8. The apparatus of claim 1, wherein the fan is positioned between about 0 inches and about 10 inches below the top end of the housing.
 9. The apparatus of claim 1, further comprising at least one air filter for filtering air passing through the airflow passageway of the housing, the air filter positioned at least 20 inches below the fan.
 10. The apparatus of claim 1, further comprising at least one air filter for filtering air passing through the airflow passageway of the housing, and wherein a second height is defined between the bottom end of the housing and the top end of the housing, and wherein a third height is defined between the at least one filter and the fan such that the third height is more than about half of the second height.
 11. The apparatus of claim 1, further comprising at least one air filter for filtering air passing through the airflow passageway of the housing, and wherein a second height is defined between the bottom end of the housing and the top end of the housing, and wherein a third height is defined between the at least one filter and the fan such that the third height is more than about two thirds of the second height.
 12. The apparatus of claim 1, further comprising at least one air filter having a rectangular shape for filtering air passing through the airflow passageway of the housing.
 13. The apparatus of claim 1, further comprising at least one air filter defining a filtration surface area for filtering air passing through the airflow passageway of the housing, and wherein the airflow passageway of the housing has a cross-sectional area less than the filtration surface area.
 14. An apparatus for circulating air comprising: a) a housing having an airflow passageway with a bottom end defining an air intake and a top end defining an air outlet; b) a support member for supporting the housing and for disposing the air intake above a support surface; c) a fan positioned within the airflow passageway of the housing; and d) a drive coupled to the fan for operating the fan so as to blow air from the air intake to the air outlet e) wherein the fan and the air outlet are configured such that the air exiting the air outlet has a flow direction with a significant vertical component and a significant lateral component.
 15. A system for circulating air comprising: a) an air circulator comprising: i) a housing having airflow passageway with a bottom end defining an air intake and a top end defining an air outlet; ii) a support member for supporting the housing and for disposing the air intake above a support surface; iii) a fan positioned within the airflow passageway of the housing; and iv) a drive coupled to the fan for operating the fan so as to blow air from the air intake to the air outlet; b) a first temperature sensor for measuring air temperature in a lower portion of a building; c) a second temperature sensor for measuring air temperature in an upper portion of the building; d) a controller for determining a temperature differential based on measurements from the first and second temperature sensors, wherein the controller operates the fan based on the temperature differential.
 16. The system of claim 15, wherein the controller adjusts a fan speed for the fan based on the temperature differential.
 17. The system of claim 16, wherein the controller outputs an AC electrical signal having a frequency for operating the fan, and wherein the controller adjusts the frequency to control the fan speed.
 18. The system of claim 17, wherein the AC electrical signal output by the controller has a substantially constant voltage.
 19. The system of claim 15, wherein the fan is positioned substantially adjacent to the top end of the housing.
 20. The system of claim 15, wherein the fan and the air outlet are configured such that the air exiting the air outlet has a flow direction with a significant vertical component and a significant lateral component. 